A 72-year-old on chronic warfarin for atrial fibrillation comes for routine follow-up. After reviewing the EHR, which finding requires the MOST urgent intervention?
Chart/Exhibit
Choose your responses, then check the answer.
Explanation
Choice 2 is the most urgent — sulfamethoxazole-trimethoprim (Bactrim) is a high-risk warfarin interaction (potentiates anticoagulation by displacing warfarin from albumin and inhibiting CYP2C9 metabolism), and the INR of 6.8 with new bruising indicates clinically significant overshoot with bleeding risk. Action: hold warfarin, notify provider, anticipate vitamin K (oral 2.5-5 mg if no major bleeding) or PCC if major bleeding, monitor for bleeding signs. Choice 1 (consistent spinach) is fine because warfarin patients should keep vitamin K intake CONSISTENT, not avoid it. Choice 3 (green tea) is consistent and no INR change implied. Choice 4 (lisinopril) has no significant warfarin interaction.
The "consistent vitamin K diet" is the most-tested warfarin teaching point — patients should NOT avoid green vegetables; they should keep intake CONSISTENT week-to-week. The high-risk antibiotic interactions (Bactrim, metronidazole, fluconazole, ciprofloxacin) potentiate warfarin and elevate INR within days. Memorize antibiotic interaction list for any warfarin patient.
72-year-old on chronic warfarin for atrial fibrillation comes for routine follow-up. The nurse reviews the chart for medication reconciliation and dietary review.
Warfarin and antibiotics — Sulfamethoxazole-trimethoprim, metronidazole, fluconazole, ciprofloxacin elevate INR; check INR within 3-5 days of new antibiotic.
Consistent vitamin K diet — Maintain steady intake of green leafy vegetables (NOT avoid); large fluctuations cause INR instability.
INR > 5 management — Hold warfarin, vitamin K oral 2.5-5 mg if no major bleeding; PCC + IV vitamin K + reversal for major bleeding; close monitoring.